1. Field of the Invention
The present invention generally relates to high temperature fasteners and more particularly to hooks for a hook and loop attachment in high temperature environments.
2. Background Description
Spacecraft, such as the space shuttle, hypersonic air-breathing vehicles, and even some state of the art aircraft, are subjected to temperature extremes, e.g., when leaving and re-entering the atmosphere. The skin of a hypersonic vehicle, for example, reaches temperature extremes in excess of 3000° F. (1650° C.) from skin friction and shockwave formation. In the case of space vehicles, very low temperatures are encountered in orbit while extreme, high temperatures (e.g., in excess of 1600° C.) are encountered in re-entry. Typically, very low-density, high-temperature insulation is used either inside (e.g., in the passenger cabin and cargo bays) or outside the vehicle (e.g., space shuttle blankets and tiles) to insulate spacecraft components and structure from these extreme temperatures. Insulation also may be used as a heat barrier between the engines and the vehicle structure and components.
Insulation is typically attached using silicone adhesives. Unfortunately, while a typical state-of-the-art silicone resin adhesive may work well below 500° F. (260° C.), these state-of-the-art silicone adhesives fail at higher temperatures. In-flight adhesive failure for externally mounted insulation can lead to catastrophic vehicle failure within seconds. Consequently, it may be necessary to use mechanical fasteners to mount the high-temperature insulation and hold it in place. In a typical spacecraft, where payload weight costs are high, cumbersome mechanical fasteners can increase vehicle weight. Moreover, both of these approaches, using state-of-the-art adhesives or mechanical fasteners, can be labor intensive (i.e., costly) to install and installation errors are difficult to correct. Further, failures are equally difficult/costly to repair.
Thus there is a need for a lightweight, high-temperature fastener that is simple to install and maintain and especially for a lightweight, high-temperature fastener for use in hypersonic and reusable space vehicles.